Regression: serial: imx: overrun errors on debug UART

[Sergey Organov]

"Linux regression tracking (Thorsten Leemhuis)"
<regressions at leemhuis.info> writes:

> Hi, Thorsten here, the Linux kernel's regression tracker. Top-posting
> for once, to make this easily accessible to everyone.
>
> Stefan, was this regression ever solved? It doesn't look like it, but
> maybe I'm missing something.
>
> If it wasn't solved: what needs to be done to get this rolling again?

Hi Thorsten,

Not Stefan, but as far as I can tell, the problem is that on Stefan's
build the kernel has rather large periods of interrupts being disabled,
so any attempt to decrease IRQs frequency from UART by raising FIFO IRQ
threshold causes "regression" that manifests itself as missing
characters on receive. I'm not sure if it's tuning FIFO level that is in
fact a regression in this case.

Solving this would need to identify the cause of interrupts being
disabled for prolonged times, and nobody volunteered to investigate this
further. One suspect, the Linux serial console, has been likely excluded
already though, as not actually being in use for printk() output.

-- 
Sergey Organov